I'm certain I have a vacuum leak somewhere, but haven't had a chance to get it checked out yet. When I try to engage the 4wd, vents go to defrost, and I never get it to engage, even with the light on.

When I change the hubs from auto to lock, everything locks in as expected...

My question. Can I leave the hubs in the lock position for normal driving, as long as I have the ESOF switch in the 2h position?

The hubs are new last year, and I do not want to muck them up... With all the snow we've been getting around here, and the lack of plowing, I've been locking them when I need them, and putting back to auto when I don't.

Thanks for any guidance/replies!

 

If the roads are dry in your area I don't think you want to lock up and run in 4X4.I don't think the switch means anything if you lock hubs into 4 wheel drive.

 

You can run your hubs manually locked as many of us do during bad weather and engage the 4x4 only when needed . However, the additional rotating mass does have a negitive impact on fuel mileage. Keep looking for you vacuum leak.

 

Thanks for the info-I stand corrected

 

Ok, that's what I was looking for. I was looking for a good explanation as to what is actually happening when it was in auto vs lock. When the weather is bad, I will just put into lock and engage 4wd when I need it. And then just switch back to auto when I don't need it.

I figured it would affect gas mileage, and haven't been leaving it there. But my daily driving has me going from mostly unplowed streets, to clear roads, then back to unplowed streets, with speeds over 45-50 on the clear patches... And I knew that if 4wd was engaged, I didn't want to be going that speed. But it was getting to be a pain to switch back to auto when I got to those spots.

I know I need to track down the vacuum leak, but just haven't had time lately. Its first on my list for January... once things slow down a bit.

Thanks!

 

I locked my hubs last week or the week before, when we got around 3 inches of flaky-icy stuff. I don't even notice them locked anymore. They usually stay that way all winter.

For the record (and not sure why this is in the V10 forum):

The hubs are a separate system from the transfer case. The light on the dash means the TRANSFER CASE is engaged, NOT the hubs.

If the hubs fail to lock, there is no feedback that they didn't engage.

 

I just finished paying through the nose tracking down and fixing my the auto function of my hubs 2 days ago, in doing so I researched and learned all the details and the exact working order of the ESOF system used in the super duties. I know this info is on this site somewhere but I run though a quick refresher.

When you flip the switch the switch basically does two things, it send a signal to a servo motor on the transfer case which puts the transfer case into 4 high. The second thing it does is send a signal to a vacuum solenoid which pulls 25psi of vacume to each hub for 45 seconds. After 45 seconds the vacuum goes to 0 psi and the hubs and transfer case should be all locked in. When you flip the switch back to 2wd the reverse happens. The transfercase is shifted back to 2wd and hubs are unlocked with an 8 psi vacuum pull for 45 seconds which unlock the front hubs. It really is a simple system. the lockouts on the hubs are a secondary system that can be used if for any reason the vacuum system doesn't actuate the hubs. When you lock the front hubs manualy by turning them to lock the front axle is now locked to the front tires and will be turning no matter what position you'r dash switch is turned to (2wd or 4wd). Switch them back to auto and they should be unlocked.

If you have problems with the front hubs not locking it is simply an expensive process of elimination. start by pulling each line of the the vacuum solenoid and check to make sure the solenoid is woking as previously described. next check the vacuum lines to the hubs, pul them off at the hubs and see if they hold pressure and make sure they don't have debris in them and that they are not collapsing under vacuum. It's nothing more than standard vacuum line so my suggestion is to skip this step and just replace the line, it doesn't cost hardly anything and is easily done. if all checks out down to where the vacuum line goes to the hubs then it's time to get the wallet out because you'll be replacing Hub Seals or the Hubs themselves or both!

I just went through this as mine would lock fine but as soon as the solenoid quit pulling vacuum after 45 seconds I the hubs would unlock. I had the seals replaced first as they are less than 1/2 the price of the hubs. there is some labor involved hear because you basically have to pull the axles shafts out to get them to pop out. my bill for this was $385.46 for labor and parts. this didn't fix the problem! Mother !$#%24%@$%^$%^&5!!! So, I was down to the hubs themselves. Keep in mind there are no aftermarket parts for this system, you get to buy from a Ford Dealership and the price is reflective of that. Hubs are around $300 a piece; all in all I was in for more than $750 in parts between hubs and seals and when it's tore down I didn't have time to go internet shopping which may or may not have worked out. I suggest checking before you tear into it in case you can save some money that way. with labor, trouble shooting, & parts the total to get everything back up and running was $1,250.28 with tax!

If you want to eliminate the auto portion of the hubs you can simply change them out and replace them with Warns or MileMarker lockouts, and cap the vacuum line up at the vacuum solenoid. this will only cost $200-$250 for parts and if you have the time, isn't very hard to do. if you have a shop do it, it'd likely cost about $400. You'll have to get out and lock the hubs to go into 4wd but it'll be a lot easier on the pocket book and you'll likely never have to deal with the hub issue as long as you own the truck!

After I replaced the seals and was in for $385 I was pissed and determined to make it right and it cost me dearly! I also likely have to deal with this again in another 5-7 years if I keep the truck that long, arg!

Good luck, hopefull it's nothing more than a vacuum line!

 

Option 2, which I forgot to add, is to simply cap the vacuum lines so the rest of the vacuum system works properly and use the stock hubs as lockouts. This is of course assuming your lockout are fee and you can turn them without a plyers, many don't turn freely at which point it's hub replacement time one way or another! Mine were free so I never actaully went without 4wd.

 

If you cap the vacuum system off...be sure to eliminate the solenoid from the system. My truck had already been changed over to Warn manual hubs with the auto 4x4 hubs capped off downstream of the solenoid. Well...the solenoid began to leak vacuum, make sure to eliminate it if you chose to go the manual route.

 

SLE is right on, but got taken on the hubs. I went through the same thing earlier this year but only needed one. Would not turn from lock to Auto. Paid $150 for hub and $90 for seals. Labor on me (priceless).

 

I have a 99 F350 4x4 DRW V10 with 335,000 mi. At about 300,000 my hubs stopped locking auto. Found the vacum hose between hub and body had rotted and had holes in it. Replaced both sides and a vacum hose at the sol. and it worked like a charm.

 

Thank you for al the info. I have ordered the Warn hubs. The tip to block the vacume line is good for me. I checked my pump and it stops rumnning when I plug it by finger. I think this means the pump is working correctly. When I cap the lines to the hubs will my defrost / MAX AC operation go back to normal operation?

The 4X gave out in the snow. I got out and put chains on the front thinking the ice and incline was just too much. That is when I found out I had no FWD. I could not get the hubs to lock by manual lock. As the sun was going down in the snow I had to move the chains to the rear and back down the road. Big Fun. Any suggestion on a good differential option. The stock is as good as nothing.